Commutator for rotary machine

ABSTRACT

A commutator assembly mounted on a shaft for use with electrical rotary machinery having a plurality of round conductors with insulating coatings therearound overlaid around the rotary shaft, each of the conductors being disposed in parallel relationship with respect to the shaft and including a first portion facing towards the brush assembly of the machine, a second portion uprising from the shaft serving as the riser for electrical connection, and a third bent portion located therebetween, the number of conductors being selected depending upon the number of poles, and the diameter of the conductors being predetermined in order that the parallel portions are in close contact with adjacent conductors and with the shaft, the parallel portions having coaxially disposed surfaces void of insulating material so as to serve as commutator segments which may contact with the brush assembly; supporting means for securing the conductors to the shaft including a first portion made of an insulating material disposed in the spaces defined by the surfaces of the shaft and the adjacent conductors without covering the exposed surfaces of the conductors, and a second reinforcing portion made of insulating material for securing the bent portions to the shaft.

United States Patent 1191 Kagami- Nov. 27, 1973 COMMUTATOR" FOR ROTARY MACHINE 1 i 1 i Primary Examiner--R. Skudy [7,51 lnvemor' k gagzfizggi jzgzg Attorney-John Thomas Cella et al.

[7.3] Assignees: Canon Kabushiki Kaisha; Kabushiki Q Kaisha Meguro Seiki Seisakusho, [57] ABSTRACT Toky, japan 7 A commutator assembly mounted on a shaft for use with electrical rotary machinery having a plurality of [22] Med: 1972 round conductors with insulating coatings therearound [2]] Ap l, N 247, 99 overlaid around the rotary shaft, each of the conduc- 1 tors being disposed in parallel relationship with re- Related Apphcat'on Data spect to the shaft and including a first portion facing Continuation of g- 17, 1970, towards the brush assembly of the machine, a second abandmed' portion uprising from the shaft serving as the riser for electrical connection, and a third bent portion located Forelgn Application Prlomy 3" therebetween, the number of conductors being se- Aug. 20, 1969 Japan 44/65814 lected depending upon the number of poles, and the v diameter of the conductors being predetermined in [52] US. Cl.....-. 310/235, 310/236 order that the parallel portions are in close contact [51] Int. Cl. H02k 13/04 with adjacent conductors and with the shaft, the paral- [58] Field of Search 310/232, 235, 236, lel portions having coaxially disposed surfaces void of 310/237, 233 insulating material so as to serve as commutator seg- I ments which may contact with the brush assembly; [56] I References Cited supporting means for securing the conductors to the UNITED STATES PATENTS shaft including a first portion made of an insulating 2 696,570 12 1954 Pandapas 310/235 material disposed in the Spaces defined by the surfaces 23999956 9/196] Faulhaber 310/235 of the shaft and the adjacent conductors without cov- 2,4g6'875 11/1949 Pollock 310/236 ering the exposed surfaces of the conductors, and a 3,148,439 9 1964 Showlater 310 235 second reinforcing portion made of insulating material 1,464,184 8/1923 1 Mansbendel 310/236 for securing the bent portions to the shaft.

403,905 5/1889 Blades. .310/236 1,536,323 5/1925 Caruso 310/237 4 Clam, 7 Drawing Flgures PAIimfuuuvzmla SHEET 2 OF 2 FIG. 5

COMMUTATQ'R FOR ROTARY MACHINE This is a continuation of application Ser. No. 64,325,

filed Aug. 17, 1970 fOrFCOMMU'ITATOR FOR- R- TARY MACHINE, now abandonedf The present'invention relates to a commutator for rotary machines and more particularly to a commutator which is especially suited for use with miniaturized rotary machines and'a method for manufacture thesame. Y A rotor of an electric rotary machine is provided with a commutator which comprises a plurality of segments assembled into a drumlike cylinder and insulation is placed between commutator segments and between the segments and theshaft to provide electrical insulation.

The commutator segments are generally made of high drawn copper having a high conductivity and insulation is generally made by micanite having better quality.

directlyjoinedtothem through risers. The commutatorsegments are circumferentially and beer of segments is determinedd'epending upon the number of poles. To. ensur'e the process of current reversal in-the armature windings in combination with brushes, the commutator segments must be uniformly equidistantly spaced apart from one another and elec- The segments are directly joined to the windingsor in equidistantly' spaced apart from one another. The num-' trically insulated from one another. The commutators .for miniaturized electric rotary machines having a small inertia must be of course miniaturized, but the arrangement and adjustment of the segments become exceedingly difficult. The greater the number'of poles, the more difficult the arrangement and adjustment of commutator segments become, i

' .Itis one of the objectsofthe present inventionto prothe circumference of a circle into a=drumlike cylinder in close contact with one another and the insulator coatings of the conductors onthe outer peripheral surface of the drumlike conductor assembly are partially removed to provide the surfacesof the commutatorsegments for contact with'brushes.

According to another aspect of-the present invention, a plurality of insulated conductors are overlaid around a shaft of a rotary machineor-another shaft to be coupled to the shaft of the rotary machine in close contact a drumlike cylinder and one end faces of the conducq tors are machined so as to provide the surfaces of commutator segments for contact with brushes. The commutator thus assembled may be removed from thejig and mounted upon the shaft of a rotary machine.

According to another aspect of the present invention, an adhessive insulating material is filled into the spaces between the conductors and an adhessive reinforcingmaterial may be applied to them. Alternatively, the conductors may be insulated with an insulator having adhessiveness so that the assembled conductors may be securely joined together by applying heat.

' The present invention will become more apparent from the following description of the preferred embodiments taken'in conjunction with the accompanying,-

drawings, in which:

FIG. 1 is a diagrammatic front view of a first embodimentof a commutator in accordance with the present 1 invention;

FIG. 2 is a sectional view taken along the-line A"-A" of FIG. 1;

FIG. 3 is a schematic view illustrating arotor pro- I vided with the commutator shownin FIGS. 1 and 2;

FIG. 4 is a front view of a second embodiment of-a commutator in accordance with the present invention;-

FIG. 5 is a sectional view taken along the line B-B" of FIG. 4;

FIG. 6 is a schematic view illustrating a rotor carrying,

the commutator shown in FIGS. 4 and 5;- and FIG. 7 is a fragmentary view illustrating the joint between the adjacent conductors of the commutator in accordance with thepresent invention.

Referring to FIG. 1, along the axis of a shaft 10 are circumferencially arrangeda plurality of round conductors l1, l2, l3, l4 and 15 having the insulators I1", 12, 13, 14' and 15 coatedtherearound. The conductors 11 15 are L-shaped as best shown inaFIG. 2 to provide the upright portions which serve as the risers.

The diameters of the insulated conductors 1'1 15 must be suitably selected..More specifically, when the 'diameters are too small, the conductors arranged along the with one another and the spaces between the conduc- I tors and between the conductors and the shaft are filled with an insulating adhesive agent so that the conductors may be securely held in position. The -outer-peripheral surface of the conductorassembly is concentrically machined by for example agrinding machine so as to remove the insulator coatings of th'e conductors.

According to another aspect ofthe present invention,

a plurality of insulated conductors are overlaid around a jig or the like in close contact with one another into axis of the shaft 10 would be spaced apa'rtfrom one an-: other too much while when the diameters are too greater, the conductors 11 l5 wouldnotbe disposed in a symmetrical arrangement to the shaft 10. That is,

the diameters must be so selected that the conductors 11 15 may be arranged around the shaft 10in such a manner that they are in close contact withone another and with the shaft 10. A suitable member such as asleeve may be interposed between the shaft 10* and the conductors 11 15. An insulating material 16 such; as epoxy resin may be filled in the spaces between the conductors and shaft so that the conductors may be securely held in position. In order'to further secure the attachment of the conductors 11 1 5, suitable rein forcing member 17 may be applied to the bent portions of the conductors l1 15.

The conductors 1 l 15 arranged securely around theshaft 10 are concentrically machined to partially remove their insulators 1 l l5 and to have the machine surfaces 12 of the conductors 11 l5 laid'in a cylindri-,

cal surface concentric with the shaft 10 as shown in FIGS. 1 and 2. Therefore, the machined surfaces 12, of the conductors l1 15 serve as the surfaces of the: cummutator segments or bars with whichmake: contact" the brush assemblies (not shown). The'outerior of the assembly of the conductors ll 15 are concentrically whereby the commutator segments or bars may be provided in a simple and effective manner. FIG. 3 shows a rotor provided with the commutator of the type described with reference to FIGS. 1 and 2. The commutator 100 is mounted on the shaft concentrically of the rotor 101 and the brushes 102 and 103 are made in contact with the commutator segments radially of the ranged around the peripheral surface of a jig (not shown) whose diameter is greater than that of the shaft. As explained above, the diameter of the conductors 2l-38 must be so selected that the conductors may be overlaid in close contact with one another and the jig. The overlaid conductors 21-38 are securely held in position by means of the insulating material as described in the first embodiment with reference to FIGS. 1 and 2 while the reinforcing member 39 may be applied to the bent portions of the L-shaped conductors. Sincethe commutator assembly must be removed from the jib, means must beprovided in order to prevent the insulat ing material from being adhered to the jig. For example instead of the insulating material, the insulators 71 and 72' of the conductors 71 and 72 shown in FIG. 7 may be imparted with thermal adhessiveness so that when heat is applied after the conductors are overlaid around the periphery of the jig or the like, they may be securely adhered to each other at 73 in FIG. 7 and held in position. In this manner, the commutator assembly may be readily removed from the jig or the like.

Referring back to FIGS. 4 and 5, the end faces of the conductors 21-38 serve as the surfaces of the commu- 'tator segments. For this purpose, the end faces of the conductors are ground to give a fine surface finish so that the brush assemblies may smoothly make contact with them. The commutator segments are electrically insulated by the insulator coatings 21' 38 of the conductors and are uniformly arranged. FIG. 6 is a schematic view illustrating a rotor provided with the commutator assembled in the manner described with reference to FIGS. 4 and 5. A rotor 201 and a commutator 202 are carried by a shaft 200. Since the commutator 202 lwhich is slidably in contact with the brushes 203 and 204 is not assembled directly around the shaft 200, it must be mounted upon the shaft 200 directly or indirectly utilizing'for example a sleeve in any suitable manner.

According to .the present invention, the commutator segments may be uniformly arranged so that the adjustment after the assembly is not required. .No shortcircuit between the commutator segments will occur because they are electrically insulated from one an.- other by their own insulator coatings. Furthermore, the commutators may be miniaturized with a high degree of accuracy so that the rotary machines themselves may be miniaturized. What is claimed is:

l. A commutator assembly mounted on a shaft for use with an electric rotary machine having a rotor rotatable with the shaft comprising:

a plurality of round conductors overlaid around said rotor shaft and having electrical insulating coatings therearound, each of said conductors being parallel to said shaft and comprising, a portion facing towards a brush assembly of said machine, a portion uprising from the shaft serving as a riser for electrical connection, and a bent portion located therebetween, the number of said conductors bring selected depending upon the number of poles, and the diameter of said conductors being predetermined in order that said parallel portions are in close contact with adjacent conductors and with the shaft, said parallel portions having coaxially exposed surfaces void of insulating material so as to serve as commutator segments which make contact with the brush assembly;

supporting means for securing said conductors to the shaft comprising, a first portion made of an insulating material disposed in the spaces defined by the surfaces of the shaft and the adjacent conductors without covering saidexposed surfaces of each conductor, and a second reinforcing portion made of insulating material for securing said bent portions to the shaft.

2. A commutator as defined in claim 1 wherein said exposed surfaces of said conductors are concentrically disposed one with respect to the other and each having a smooth finish to make contact with said brush assembly during operation.

3. A commutator as defined in claim 1, wherein said plurality of insulated conductors are arranged in a cylindrical configuration.

4. A commutator as defined in claim 1 wherein said plurality of insulated conductors have coatings of an adhesive insulating material disposed on their unexposed surfaces facing toward said shaft and the adjacent conductors. 

1. A commutator assembly mounted on a shaft for use with an electric rotary machine having a rotor rotatable with the shaft comprising: a plurality of round conductors overlaid around said rotor shaft and having electrical insulating coatings therearound, each of said conductors being parallel to said shaft and comprising, a portion facing towards a brush assembly of said machine, a portion uprising from the shaft serving as a riser for electrical connection, and a bent portion located therebetween, the number of said conductors bring selected depending upon the number of poles, and the diameter of said conductors being predetermined in order that said parallel portions are in close contact with adjacent conductors and with the shaft, said parallel portions having coaxially exposed surfaces void of insulating material so as to serve as commutator segments which make contact with the brush assembly; supporting means for securing said conductors to the shaft comprising, a first portion made of an insulating material disposed in the spaces defined by the surfaces of the shaft and the adjacent conductors without covering said exposed surfaces of each conductor, and a second reinforcing portion made of insulating material for securing said bent portions to the shaft.
 2. A commutator as defined in claim 1 wherein said exposed surfaces of said conductors are concentrically disposed one with respect to the other and each having a smooth finish to make contact with said brush assembly during operation.
 3. A commutator as defined in claim 1, wherein said plurality of insulated conductors are arranged in a cylindrical configuration.
 4. A commutator as defined in claim 1 wherein said plurality of insulated conductors have coatings of an adhesive insulating material disposed on their unexposed surfaces facing toward said shaft and the adjacent conductors. 